Staging

Like many malignancies, penile cancer can spread to other parts of the body. It is usually a primary malignancy, the initial place from which a cancer spreads in the body. Much less often it is a secondary malignancy, one in which the cancer has spread to the penis from elsewhere. The staging of penile cancer is determined by the extent of tumor invasion, nodal metastasis, and distant metastasis.[2]

Stage IIIa—There is deep invasion into the penis and metastasis in one lymph node.

Stage IIIb—There is deep invasion into the penis and metastasis into multiple inguinal lymph nodes.

Stage IV—The cancer has invaded into structures adjacent to the penis, metastasized to pelvic nodes, or distant metastasis is present.

HPV positive tumors

Human papillomavirus prevalence in penile cancers is high at about 40%. HPV16 is the predominant genotype accounting for approximately 63% of HPV-positive tumors. Among warty/basaloid cancers the HPV prevalence is 70–100% while in other types it is around 30%.[1]

Genital warts—Genital or perianal warts increase the risk of invasive penile cancer by about 3.7 times if they occurred more than two years before the reference date.[7] About half of men with penile cancer also have genital warts, which are caused by HPV.[11]

Hygiene and injury

Smegma—Smegma, a whitish substance that can accumulate beneath the foreskin, is associated with greater risk of penile cancer.[5][14] The American Cancer Society suggests that smegma may not be carcinogenic, but may increase the risk by causing irritation and inflammation of the penis.[5]

Balanitis and penile injury—Inflammation of the foreskin and/or the glans penis (balanitis) is associated with about 3.1 times increased risk of penile cancer.[7] It is usually caused by poor hygiene, allergic reactions to certain soaps, or an underlying health condition such as reactive arthritis, infection, or diabetes.[3] Small tears and abrasions of the penis are associated with about 3.9 times increased risk of cancer.

Phimosis—Phimosis is a medical condition where the foreskin cannot be fully retracted over the glans. It is considered a significant risk factor in the development of penile cancer (odds ratio of 38–65).[7] Phimosis may also be a symptom of penile cancer.[4]

Paraphimosis—Paraphimosis is a medical condition where the foreskin becomes trapped behind the glans. It is considered a risk factor for the development of penile cancer.[5]

Circumcision—Some studies show that circumcision during infancy or in childhood may provide partial protection against penile cancer, but this is not the case when performed in adulthood.[15] It has been suggested that the reduction in risk may be due to reduced risk of phimosis;[5][15] other possible mechanisms include reduction in risk of smegma and HPV infection.[5]

Other

Age—Penile cancer is rarely seen in men under the age of 50. About 4 out of 5 men diagnosed with penile cancer are over the age of 55.[5]

Lichen sclerosus—Lichen sclerosus is a disease causing white patches on the skin. Lichen sclerosus increases the risk of penile cancer.[12][16] As the exact cause of lichen sclerosus is unknown, there is no known way to prevent it.[12]

Tobacco—Chewing or smoking tobacco increases the risk of penile cancer by 1.5–6 times depending on the duration smoking and daily number of cigarettes.[1][7][12]

Prevention

The use of condoms is thought to be protective against the HPV associated penile cancer.[1]

Good genital hygiene, which involves washing the penis, the scrotum, and the foreskin daily with water, may prevent balanitis and penile cancer. However, soaps with harsh ingredients should be avoided.

Circumcision during infancy or in childhood may provide partial protection against penile cancer. Several authors have proposed circumcision as a possible strategy for penile cancer prevention;[1][12][17] however, the American Cancer Society points to the rarity of the disease and notes that neither the American Academy of Pediatrics nor the Canadian Academy of Pediatrics recommend routine neonatal circumcision.[5]

Phimosis can be prevented by practising proper hygiene and by retracting the foreskin on a regular basis.

Paraphimosis can be prevented by not leaving the foreskin retracted for prolonged periods of time.

Amputation (penectomy)—a partial or total removal of the penis, and possibly the associated lymph nodes.

Radiation therapy is usually used adjuvantly with surgery to reduce the risk of recurrence. With earlier stages of penile cancer, a combination of topical chemotherapy and less invasive surgery may be used. More advanced stages of penile cancer usually require a combination of surgery, radiation and chemotherapy.
In addition to all the above, treatment of the underlying disease like brucellosis, is important to limit disease recurrence.

Prognosis

Prognosis can range considerably for patients, depending where on the scale they have been staged. Generally speaking, the earlier the cancer is diagnosed, the better the prognosis. The overall 5-year survival rate for all stages of penile cancer is about 50%.[2]

Epidemiology

Penile cancer is a rare cancer in developed nations with annual incidence varying from 0.3 to 1 per 100,000 per year accounting for around 0.4–0.6% of all malignancies.[1] The annual incidence is approximately 1 in 100,000 men in the United States,[18] 1 in 250,000 in Australia,[19] and 0.82 per 100,000 in Denmark.[20] In the United Kingdom, fewer than 500 men are diagnosed with penile cancer every year.[11][21]

However, in the developing world penile cancer is much more common. For instance, in Paraguay, Uruguay, Uganda and Brazil the incidence is 4.2, 4.4, 2.8 and 1.5–3.7 per 100,000, respectively.[1][7] In some South American countries, Africa, and Asia, this cancer type constitutes up to 10% of malignant diseases in men.[1] The lowest incidence is in Israeli Jews—0.1 per 100,000.

The lifetime risk has been estimated as 1 in 1,437 in the United States and 1 in 1,694 in Denmark.[22]